U.S. patent number 6,131,701 [Application Number 09/458,797] was granted by the patent office on 2000-10-17 for apparatus and method for cleaning and fluid exchange of a low-flow automatic transmission.
This patent grant is currently assigned to Wynn Oil Company. Invention is credited to Michael Camacho, Mark Sasaki.
United States Patent |
6,131,701 |
Camacho , et al. |
October 17, 2000 |
Apparatus and method for cleaning and fluid exchange of a low-flow
automatic transmission
Abstract
A fail-safe transmission service machine (12) allows old ATF to
be pumped out of a transmission (10b) as a vehicle engine (10a)
runs while the vehicle (10) is stationary. The machine (12)
responsively pumps a matching volume of new ATF into the
transmission so that dry running of the transmission can not occur.
If the supply of new ATF runs out or if power to the service
machine (12) is interrupted, the machine reverts to closed loop
fluid circulation for the transmission. A hydraulic rectifier (42)
provides for universal connection of hoses between the transmission
cooler fluid circulation loop (39) of the vehicle (10) and the
service machine (12). An electrically driven assistance pump (94)
allows the service of vehicles which have low-flow or low-pressure
transmission pumps.
Inventors: |
Camacho; Michael (Rancho
Cucamonga, CA), Sasaki; Mark (Riverside, CA) |
Assignee: |
Wynn Oil Company (Azusa,
CA)
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Family
ID: |
22311919 |
Appl.
No.: |
09/458,797 |
Filed: |
December 10, 1999 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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106530 |
Jun 29, 1998 |
|
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|
816486 |
Mar 13, 1997 |
5806629 |
Sep 15, 1998 |
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Current U.S.
Class: |
184/1.5; 137/240;
137/270; 137/597 |
Current CPC
Class: |
F01M
11/0458 (20130101); F02B 77/04 (20130101); F16H
57/0402 (20130101); F16H 57/0408 (20130101); F16H
57/0493 (20130101); F16H 61/0025 (20130101); F01M
11/04 (20130101); F01M 2011/0466 (20130101); Y10T
137/4259 (20150401); Y10T 137/5196 (20150401); Y10T
137/87249 (20150401) |
Current International
Class: |
F01M
11/04 (20060101); F16H 57/04 (20060101); F16C
003/14 () |
Field of
Search: |
;184/1.5
;137/240,270,597 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Bucci; David A.
Assistant Examiner: Kim; Chong H.
Attorney, Agent or Firm: Miller; Terry L.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application is a Divisional application of U.S.
application Ser. No. 09/106,530, filed Jun. 29, 1998, now pending,
which is a Continuation-in-Part of U.S. application Ser. No.
08/816,486, filed Mar. 13, 1997, now U.S. Pat. No. 5,806,629,
issued Sep. 15, 1998.
Claims
What is claimed is:
1. For use with an automotive vehicle having an engine and an
automatic transmission, the transmission having an internal pump
operated when the engine drives the transmission so that ATF from
the transmission is pumped through an external fluid circulation
loop of the vehicle and back to the transmission, a method of
exchanging used ATF from the transmission with new ATF comprising
steps of:
providing a source of new ATF;
opening said external fluid circulation loop to provide a pair of
loop connections, so that one loop connection of said pair of loop
connections provides outflow of old ATF to waste;
flowing new ATF from said source to the other loop connection of
said pair of loop connections so as to effect a pseudo-closing of
said opened external fluid circulation loop;
providing a first conduit for conducting ATF from said one loop
connection to one bi-directional flow port of a unitary hydraulic
rectifier, and providing a second conduit for conducting ATF from
another bi-directional flow port of said unitary hydraulic
rectifier to said other loop connection;
providing the unitary hydraulic rectifier with a unitary body
defining four ports, and four intersecting passages each leading
from a respective one of said four ports only to another one of
said four passages, disposing a respective one of four one-way
valves in each of said four passages, and disposing said four
one-way valves so that one port of said four ports is exclusively
an inflow port, one port of said four ports is exclusively an
outflow port, and the other two ports of said four ports each allow
bi-directional flow;
providing fluid flow communication from said exclusive outflow port
to waste, and from said source of fresh ATF to said exclusive
inflow port.
2. The method of claim 1 further including the step of providing an
electrically driven pump for assisting flow of fresh ATF from said
source to said exclusive inflow port of said unitary hydraulic
rectifier.
3. The method of claim 2 further including the step of powering
said electrically driven pump using an motor receiving electric
power from an electrical system of said vehicle during operation of
said engine.
4. The method of claim 1 further including the steps of:
providing a motor/pump unit having a motor portion receiving flow
of used ATF from said exclusive outflow port of said hydraulic
rectifier to simultaneously drive the motor portion of the
motor/pump unit, and a pump portion of said motor/pump unit
receiving fresh ATF from said source and pumping this fresh ATF to
said exclusive inflow port of said unitary hydraulic rectifier.
5. The method of claim 4 further including the step of providing
for each of said motor portion and said pump portion to displace an
equal volume of fluid during simultaneous operation of the
motor/pump unit.
6. A unitary hydraulic rectifier comprising;
a unitary body providing a housing for said unitary hydraulic
rectifier, said body being configured in plan view as a rectangular
prism having four side edges and a thickness, and said body
defining four bores each extending parallel to the plane of said
plan view and opening outwardly of said body only on a respective
one of said four side edges to define a respective one of four bore
openings;
each one of said four bores intersecting and communicating with a
next adjacent one of said four bores intermediate of an opening of
the next-adjacent bore on a respective side edge of said body and
the intersection of said next-adjacent bore with another of said
four bores, so that said four bores communicate each bore opening
with the other three of said four bore openings;
each bore opening outwardly on said body defining a respective one
of four fluid flow ports on the body, said four fluid flow ports
providing a fluid inlet port exclusively for fluid flow into said
body, a fluid outlet port exclusively for fluid flow from said
body, and a pair of bi-directional ports allowing fluid flow both
into and out of said body; and
four unidirectional flow check valves, each check valve being
interposed in a respective one of said four bores between the
opening of the respective bore and the communication of the bore
with the next-adjacent one of the four bores, and said four check
valves being disposed for unidirectional flow in the respective
ones of said four bores so as to allow fluid flow only into said
inlet port, only from said outlet port, and both into and from said
bi-directional ports.
7. The unitary hydraulic rectifier of claim 6 wherein each one of
said four unidirectional flow check valves includes a tubular body
sealingly received into a respective one of said four bores, said
tubular body having a stepped through bore defining a tapered
seating surface, a movable valve member received into said stepped
through bore and having a conical head portion sealingly engageable
with said tapered seating surface in a first position for said
valve member to block fluid flow through said through bore of said
tubular body, said valve member including a stem portion extending
from said conical head portion to a perforate disk portion, said
perforate disk portion defining plural through perforations
allowing fluid flow through said disk portion, and a yieldable
biasing member extending between said disk portion and said tubular
body to yieldably urge said conical head portion into said first
position, so that fluid pressure is applied to said conical head
portion via said perforations of said disk member unseat said
conical head portion to allow fluid flow through said tubular
body.
8. Apparatus for simultaneously exchanging used ATF with new ATF in
an automotive automatic transmission during operation of the
transmission, and while an internal pump of the transmission pumps
ATF from the transmission in an external fluid circulation loop and
back to the transmission, said apparatus comprising:
a source of new ATF;
means providing a pair of loop connections to the external fluid
circulation loop so that the loop is opened and one loop connection
of said pair provides flow of old ATF to waste; and means for
flowing new ATF from said source to the other loop connection of
said pair of loop connections so as to effect a pseudo-closing of
said opened external fluid circulation loop;
a unitary hydraulic rectifier with a unitary body defining four
ports, the unitary body defining also four intersecting passages
each leading from a respective one of said four ports only to
another one of said four passages, four one-way valves disposed one
in each of said four passages, each one of said four one-way valves
being so disposed that one port of said four ports is exclusively
an inflow port, one port of said four ports
is exclusively an outflow port, and the other two ports of said
four ports each allow bi-directional flow;
a first conduit for conducting ATF from said one loop connection to
one bi-directional flow port of said unitary hydraulic rectifier, a
second conduit for conducting ATF from another bi-directional flow
port of said unitary hydraulic rectifier to said other loop
connection;
means providing fluid flow communication from said exclusive
outflow port to waste, and means providing flow of fresh ATF from
said source to said exclusive inflow port; and
a positive displacement motor/pump unit connecting into said
external fluid circulation loop via said conduits and unitary
hydraulic rectifier so that while loop is opened old ATF from the
transmission flows via a motor portion of the motor/pump unit to
waste and drives a pump portion of said motor/pump unit;
whereby, either one of said first conduit and said second conduit
may be connected individually to either one of said pair of loop
connectors, and said unitary hydraulic rectifier provides for flow
of used ATF to waste and flow of fresh ATF from said source to said
transmission.
9. The apparatus to claim 8 further including an assistance pump
flowing new ATF from said source through said pump portion of said
motor/pump unit to said automatic transmission so as to effect a
pseudo-closing of said external fluid circulation loop, whereby
used ATF pumped out of said transmission by said internal pump is
continuously replaced in equal volume with new ATF from said source
by said assistance pump and said motor/pump unit in
cooperation.
10. A fail-safe transmission fluid exchange machine for an
automotive automatic transmission, which automatic transmission
includes an internal pump moving automatic transmission fluid (ATF)
through an external ATF cooler in a circulation loop, said machine
comprising:
a conduit for conducting ATF from said circulation loop to a common
port of a three-way valve, said three-way valve in a first position
communicating ATF received via said first conduit from said
circulation loop to a second conduit via a normally-open (N.O.)
port, which second conduit returns ATF to said circulation loop,
said three-way valve in a second position thereof communicating ATF
from said circulation loop via a normally-closed (N.C.) port to
waste;
a yieldably-biased back-driveable actuator which when actuated
moves said three-way valve from said first to said second position
thereof and which when deactivated returns said three-way valve to
said first position by self-bias;
a container for holding a supply of new ATF;
a sensor for indicating when said container holds an adequate
supply of new ATF;
a motor/pump unit having a motor portion disposed in fluid flow
series between said N.C. port of said three-way valve and waste to
be driven by ATF pumped out of said transmission; and a pump
portion receiving new ATF from said container therefor and
supplying said new ATF pressurized via said second conduit to said
circulation loop, said motor portion and said pump portion of said
motor/pump unit being drivingly coupled to one another for
operation simultaneously in unison with each displacing an equal
volume of fluid;
an assistance pump unit drawing power from a source other than said
internal pump of said transmission, said assistance pump being in
fluid low series with said pump portion of said motor/pump unit and
flowing new ATF toward said transmission;
a control system interconnecting said sensor and said actuator to
allow actuation of said actuator to place said three-way valve in
said second position only while said sensor indicates an adequate
supply of new ATF, said control system deactivating said actuator
in the event of an inadequate supply of new ATF to allow said
three-way valve to be returned to said first position by self-bias
of said actuator; and
a unitary hydraulic rectifier with a unitary body defining four
ports, the unitary body defining also four intersecting passages
each leading from a respective one of said four ports only to
another one of said four passages, four one-way valves disposed one
in each of said four passages, each one of said four one-way valves
being so disposed that one port of said four ports is exclusively
an inflow port, one port of said four ports is exclusively an
outflow port, and the other two ports of said four ports each allow
bi-directional flow;
whereby either of said first conduit or said second conduit may be
connected in said circulation loop of said transmission so as to
receive old ATF pumped by the internal pump of the transmission,
and either one of said first conduit or said second conduit can be
connected into the circulation loop of the transmission so as to
deliver new ATF to the circulation loop, with said unitary
hydraulic rectifier providing for communication of old ATF from
said transmission to waste, and communication of new ATF from said
container into said transmission.
11. A method of exchanging used ATF with new ATF in an automotive
automatic transmission having an internal pump and an external
fluid circulation loop, said method comprising steps of:
providing a source of new ATF;
providing an assistance pump and a power source for this assistance
pump;
connecting a positive displacement motor/pump unit into said
external fluid circulation loop, so that said loop is opened and
old ATF from the transmission flows via a motor portion of the
motor/pump unit to waste by reason of pressure provided by said
internal transmission pump and assists in driving a pump portion of
said motor/pump unit;
providing a unitary hydraulic rectifier with a unitary body
defining four ports, utilizing the unitary body to define four
intersecting passages each leading from a respective one of said
four ports only to another one of said four passages, providing
four one-way valves disposed one in each of said four passages, and
disposing each one of said four one-way valves so that one port of
said four ports is exclusively an inflow port, one port of said
four ports is exclusively an outflow port, and the other two ports
of said four ports each allow bi-directional flow, and
flowing new ATF from said source through said assistance pump, said
pump portion of said motor/pump unit, said unitary hydraulic
rectifier, and to said automatic transmission so as to effect a
pseudo-closing of said external fluid circulation loop, whereby
used ATF pumped out of said transmission by said internal pump
flows via said unitary hydraulic rectifier to said pump portion of
said motor/pump unit and to waste, and the used ATF is continuously
replaced in equal volume with new ATF from said source by said
assistance pump in cooperation with said pump portion of said
motor/pump unit.
12. The method of claim 11 wherein said power source for said
assistance pump is selected from the group consisting of: an
electric motor, an air motor, and a torque motor.
13. The method of claim 12 further including the step of powering
said assistance pump using an electric motor receiving electric
power from an electrical system of a vehicle having said automatic
transmission.
14. The method of claim 11 including the step of utilizing a
positive displacement pump as said assistance pump.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is in the field of apparatus and method used
first to internally clean a transmission (i.e., by adding and
circulating a cleaning fluid to the used ATF), and then to
discharge old ATF from the automatic transmission. While the old
ATF is discharged, new ATF is simultaneously delivered into the
transmission. Thus, the apparatus and method may be used to clean
an automatic transmission and exchange the old fluid with new, all
while the transmission is installed in a vehicle, such as in an
automobile, truck or bus, for example. Particularly, the present
apparatus and method addresses the problem of servicing those
automotive vehicles having automatic transmissions with internal
transmission pumps of low-flow or low-pressure characteristics.
These low-pressure and low-flow characteristics make this type of
transmission particularly difficult to clean and service.
2. Related Technology
Many conventional machines and methodologies presently exist for
withdrawing used ATF from an automotive automatic transmission, and
for replacing this old fluid with new fluid, either sequentially or
simultaneously while the old fluid is removed or discharged from
the transmission.
The traditional method of changing the fluid in an automatic
transmission (i.e., by dropping the transmission pan and replacing
the fluid and transmission filter) has fallen into disfavor because
it leaves such a large percentage of the old fluid in the
transmission.
More favored at the present time are machines and methods which
employ the internal pump of the transmission to discharge the ATF,
while new ATF is supplied into the transmission on a volume
matching basis. The vehicle engine is ordinarily operated in order
to drive the internal pump of the transmission. This operation of
the vehicle engine is usually accomplished by running the vehicle
engine with the transmission in "neutral" or "park", with most of
the old ATF being exchanged in this way (i.e., without the drive
wheels spinning or the transmission clutches being cycled). In this
way, the old ATF is flushed from the transmission, torque
converter, ATF cooler, and connecting conduits of the transmission
system. Alternatively, the vehicle can be operated on a chassis
roller stand, allowing the drive wheels to spin and the clutches of
the transmission to be cycled. Operation of the vehicle engine
powers the internal fluid pump of the transmission and facilitates
flow of ATF through the torque converter and other parts of the
transmission system, effectively flushing out the old ATF and
replacing it with new fluid. In this latter case, the transmission
clutches will also be cycled to remove old ATF.
A cleaning machine for an automotive automatic transmission is
known according to U.S. Pat. No. 5,337,708, issued Aug. 16, 1994 to
We-Yu Chen. The '708 patent is believed to teach a transmission
fluid change machine in which an external ATF circulation loop of
the transmission is opened, with part of the machine completing
this loop in one mode of operation. The used transmission fluid,
possibly with a transmission flushing solution, is circulated in
the external circulation loop as completed by the machine. When
operated in an exchange/refill mode, the machine receives old
transmission fluid and supplies new fluid at a selected pressure or
volume delivery rate.
The machine taught by Chen is intended to be operated from the 12
volt power supply of the automobile or other automotive vehicle
being serviced. The new transmission fluid tank of this device
appears to be provided with a level sensor, so that the system can
be reverted to loop configuration (filtration/flushing) should the
level of new ATF drop too low. An external power-driven pump is
utilized to move new ATF from the fluid tank to the transmission
being serviced. However, it is not clear from this patent that in
the event the power supply to this device is interrupted or the
pump ceases to operate, that the configuration of the device is
reverted to loop form so that the transmission of the vehicle being
serviced is not damaged by being operated with insufficient ATF.
Although this patent asserts that a power failure will cause
reversion of the apparatus to loop configuration in the event of a
power failure, how this change in configuration is to be effected
or powered does not appear to be explained.
Another transmission fluid change apparatus is disclosed by U.S.
Pat. No. 5,318,080, issued Jun. 7, 1994 to James P. Viken. The '080
patent is believed to disclose an apparatus in which supply of the
new ATF is provided by a pressurized storage container, which
container is pressurized by the inflow of used ATF pumped from the
transmission by its own internal pump. The storage container has a
chamber which is separated by a flexible wall (i.e., a
rolling-diaphragm piston) into two sub-chambers expanding and
contracting in opposition. As used ATF from the transmission is
received into one sub-chamber, new ATF is displaced from the other
sub-chamber to the transmission. Another embodiment of this device
uses two separate containers, one receiving the old ATF and the
other holding new ATF. Air displaced from the one container is
routed into
the other with the idea that the air will drive the new ATF into
the transmission. A pressurized air assist to this delivery of new
fluid is provided. There is considerable uncertainty with these
machines that the rate of new fluid delivery really matches the
rate of old fluid draining from the transmission under service.
Another transmission service machine is known according to U.S.
Pat. No. 5,370,160, issued Dec. 6, 1994 to Zachary T. Parker. The
'160 patent is believed to disclose a service machine in which the
external ATF fluid return loop for the transmission is completed by
a reservoir from which the fluid is drawn by a pump. Accordingly,
in the event that operation of the pump is interrupted while the
serviced vehicle continues to operate, the transmission of the
vehicle is at risk of damage from dry running. A separate pump is
used to supply new ATF to the transmission, but this pump may
suffer from the same power supply interruption, so that the
transmission is still at risk of damage from dry running. The
Parker '160 patent does not appear to provide a closed external ATF
circulation loop for the transmission being serviced (other than
the one relying on operation of an external power-driven pump), and
does not use a three-way valve to complete or open such an external
ATF circulation loop.
Still another apparatus for exchanging the fluid of an automatic
transmission is known in accord with U.S. Pat. No. 5,447,184,
issued Sep. 5, 1995 to Eduardo Betancourt. The '184 patent is
believed to disclose an apparatus in which a reservoir for new ATF
is provided so that the volume of new fluid supplied to the
transmission can exceed the withdrawn volume. The '184 patent
appears to include a sensor operating a bell to bring the
attendant's attention to the fact that the supply of new ATF is at
risk of running out. However, if the attendant is either not close
at hand to hear the bell or is inattentive, the transmission may
still be damaged if the supply of new ATF runs out while the
transmission is being flushed. Still further, the device taught by
the '184 patent is not believed to provide any safeguard to protect
the automatic transmission in the event of a power failure to the
apparatus while the transmission is being flushed during
operation.
Finally, an apparatus for flushing an automatic transmission is
known according to U.S. Pat. No. 5,472,064, issued Dec. 5, 1995.
The feature which the '064 patent appears to contribute to the art
is the use of a conventional directional flow control valve. This
flow control valve is inserted into the fluid flow conduits
connecting the service machine to the external loop of the
transmission, and allows connection of the apparatus to the
external ATF circulation loop (i.e., the ATF cooler loop) of the
transmission with no need to take note of the direction of fluid
circulation in this loop. If the internal fluid flow direction of
the machine happens to be correct as connected, there is no need to
change the valve position. In the event the internal fluid flow
direction of the machine is opposite to that of the transmission
connection, then reversing the position of the flow control
direction valve will match the internal flow direction to the
direction of the fluid flow in the external ATF flow loop of the
transmission. This machine requires attention and manual
intervention of the technician to correct the fluid flow directions
so that service can begin in the event that by chance these
connections to the transmission are not right to begin with.
None of these conventional transmission service machines address or
solve the problem presented by some low-flow or low-pressure
automatic transmissions. That is, some transmissions have an
internal pump which does not provide the required pressure or fluid
flow volume necessary to effect exchange of the transmission fluid
(ATF) using conventional machines and methods for this purpose.
SUMMARY OF THE INVENTION
In view of the deficiencies of the conventional art, a primary
object for this invention is to avoid one or more of these
deficiencies.
A primary object for this invention it to provide an automatic
transmission service apparatus and method which allows low-flow or
low-pressure automatic transmissions to be serviced in the way
described above by simultaneous discharge of the old ATF and
replacement with new ATF.
Still another object is to provide such an apparatus and method in
which an internal hydraulic rectifier provides both for a universal
connection of the apparatus to vehicles being serviced, and also
has a novel structure which both simplifies the structure of the
machine and reduces the possibilities of fluid leakage in the
machine.
Another object is to provide a fail-safe automatic transmission
service machine.
Accordingly, the present invention provides a method of exchanging
used ATF with new ATF in an automotive automatic transmission
having an internal pump and an external fluid circulation loop, and
without limitation on the volume of ATF which can be exchanged, the
method comprising steps of providing a source of new ATF;
connecting a positive displacement motor/pump unit into the
external fluid circulation loop, so that the loop is opened and old
ATF from the transmission flows via a motor portion of the
motor/pump unit to waste by reason of pressure provided by the
internal transmission pump assisting in driving the pump portion of
the motor/pump unit, and flowing new ATF from the source through
both a low energy usage assistance pump drawing power from the
vehicle, and the pump portion of the motor/pump unit, and then to
the automatic transmission so as to effect a pseudo-closing of the
external fluid circulation loop, whereby used ATF pumped out of the
transmission by the internal pump is continuously replaced in equal
volume with new ATF from the source by the motor/pump unit.
In another aspect, the present invention provides an apparatus for
exchanging used ATF with new ATF in an automotive automatic
transmission having an internal pump and an external fluid
circulation loop, said apparatus comprising: a source of new ATF; a
positive displacement motor/pump unit for connection into said
external fluid circulation loop so that said loop is opened and old
ATF from the transmission flows via a motor portion of the
motor/pump unit to waste by reason of pressure provided by said
internal pump of the transmission assisting to drive a pump portion
of said motor/pump unit, and an assistance pump flowing new ATF
from said source through said pump portion of said motor/pump unit
to said automatic transmission so as to effect a pseudo-closing of
said external fluid circulation loop, whereby used ATF pumped out
of said transmission by said internal pump is continuously replaced
in equal volume with new ATF from said source by said assistance
pump and said motor/pump unit in cooperation.
According to yet another aspect the present invention provides a
hydraulic rectifier including a unitary body providing a housing
for the rectifier and having four intersecting bores, each bore
opening outwardly on the body to define a respective one of four
fluid flow ports on the body, said four fluid flow ports providing
two fluid inlet ports and two fluid outlet ports, and each bore
also communicating between the respective opening of that bore on
the body and another one of the four bores in a sequential
connection internally of the body; each bore adjacent to its
opening providing means for connection with a fluid flow conduit at
said opening on said body; and four unidirectional flow check
valves, each check valve being interposed in a respective one of
said four bores between the opening of the bore and the
communication of the bore with another one of the four bores, and
said four check valves being disposed for unidirectional flow in
the respective ones of said four bores so as to allow fluid flow
only from the two of the openings on said body which are inlet
opening and only from the two of the openings which are outlet
openings on said body.
A better understanding of the present invention will be obtained
from reading the following description of a single exemplary
preferred embodiment of the present invention taken in conjunction
with the appended drawing Figures. It will be understood that the
appended drawing Figures and description here following relate only
to one exemplary preferred embodiment of the invention, and as
such, are not to be taken as implying a limitation on the
invention. No such limitation on the invention is implied, and none
is to be inferred.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
FIG. 1 provides a fragmentary pictorial and somewhat schematic
depiction of an automobile having its automatic transmission
serviced by a machine embodying the present invention;
FIG. 2 is a schematic representation of automobile power train
(engine and transmission) as will as the transmission service
machine seen in FIG. 1, and depicts alternative modes of operation
(or fluid flow paths) utilized during the servicing of the
transmission;
FIG. 3, provides a perspective view of a motor/pump unit used in
the transmission service machine seen in FIGS. 1 and 2, and is
shown with the housing of this motor/pump illustrated in phantom
lines for improved clarity of description; and
FIG. 4 is a fragmentary exploded perspective view of an
electrically driven assist pump used in the embodiment of the
invention seen in FIG. 2;
FIGS. 5 and 6, respectively, are a fragmentary cross sectional view
in plan and a fragmentary cross sectional view in elevation, of the
electrically driven assist pump seen in FIG. 4;
FIGS. 7 and 8, respectively, are a front elevation view in cross
section, and a side elevation view, of a hydraulic rectifier used
in the embodiment of the machine seen in FIG. 2;
FIGS. 9 and 10, respectively, are fragmentary views, partially in
cross section showing a unidirectional check valve mechanism of the
hydraulic rectifier of FIGS. 7 and 8, and in alternative operating
positions; and
FIG. 11 provides a fragmentary view of an alternative embodiment of
the invention in which an assistance to a motor/pump unit is
provided by a torque motor.
DETAILED DESCRIPTION OF AN EXEMPLARY PREFERRED EMBODIMENT OF THE
INVENTION
Referring to FIG. 1, an automotive vehicle 10 is seen having its
automatic transmission serviced by use of a fail-safe machine 12
embodying the present invention. It will be understood that the
vehicle 10 is illustrative only, and that other types of automotive
vehicles may have their transmissions serviced by use of the
machine 12. For example, some heavy trucks and buses use automatic
transmissions, which also may be serviced in the way described
below.
In general view, it is seen that the machine 12 is connected to the
vehicle 10 in two respects. First, the machine 12 is connected by a
pair of hoses 14 and 16 to the transmission cooling fluid circuit
of the vehicle 10, as will be explained. Also, the machine 12 is
electrically connected in this case by a cable 18 to receive
electrical power from the vehicle 10. The cable attaches by clamps
18a to the appropriate terminals of the vehicle battery. The
machine 12 requires no line power (i.e., no 110 volt or 220 volt AC
power, for example), and uses only a small current of electrical
power from the vehicle 10 to operate both a fail-safe function of
the machine and a fluid flow assist function, as will be further
described below.
The machine 12 includes a cabinet 20 having wheels 22 and a handle
24 providing for the cabinet to be rolled about a service area, for
example, to an appropriate position next to a vehicle to be
serviced. The machine 12 will be seen to have a very low center of
gravity so that it is not easily tipped over while being moved and
is stable both while stationary and during such moving on its
wheels about the floor of a service area (generally indicated with
the numeral 26). Such low center of gravity is provided by the
machine 12 because essentially the entire lower portion 28 of the
cabinet defines a reservoir for new transmission fluid, providing
an exceptionally low center of gravity for the machine 12. The
front of the machine 12 is provided with a vertically extending
sight glass 28a (actually formed of break-resistant plastic tubing)
providing an indication of the fluid level in the reservoir portion
28 of the machine 12.
Still viewing FIG. 1, it is seen that during service of the
transmission of vehicle 10, the vehicle engine is run, and the
vehicle may be in neutral or park, or may be on a chassis roller
stand allowing the drive wheels of the vehicle to spin with the
vehicle stationary. In this situation, the internal pump(s) of the
transmission will be operating, and used ATF will flow from the
vehicle transmission via hose 14 to the machine 12. During an
initial transmission flushing mode of operation, the used ATF
(possibly with a flushing chemical added for this phase of
transmission cleaning during which varnish and debris in the
transmission are loosened for removal) flows back to the
transmission via hose 16. In other words, in a flushing mode of
operation, the machine 12 completes an external closed fluid flow
loop for the transmission.
However, when a service technician actuates switch 30 the machine
12 enters an AFT exchange mode of operation. In this exchange mode
of operation, used ATF flows from the transmission to machine 12,
and then to a container 32 via a hose 34 for recycling or
appropriate disposal. The hose 34 may simply be routed to a large
used-fluid storage tank maintained by some service facilities for
this purpose. The service area in this case will have access to
many conveniently located inlets to this storage tank, and the
container 32 will not be needed. Simultaneously, new ATF is
supplied by the machine 12 from the reservoir 28 into the
transmission of the vehicle via hose 16.
While this AFT exchange process is going on the fluid flow rates in
the hoses 14 and 16 are substantially matched to one another by the
machine 12. Accordingly, the fluid level in the transmission of the
vehicle 10 can not drop too low, and transmission damage from dry
running can not occur.
In the event the reservoir 28 is allowed to run out of new ATF, the
machine 12 will either not enter exchange mode, or will
automatically revert from this mode to flush (i.e., recirculation)
mode. Again, dry running of the vehicle transmission can not occur.
Also, in the event that power to the machine 12 is interrupted
(i.e., if one of the clamps 18a becomes disconnected, for example),
then the machine 12 reverts instantly to flush mode without the
need for manual attention from an attendant and without power being
required to effect this reversion to flush mode.
Attention now to FIG. 2 will reveal a schematic of the plumbing and
functional structures of the machine 12. The engine and
transmission of the vehicle 10 are indicated with numerals 15a and
10b, respectively. Those ordinarily skilled in the pertinent arts
will understand that the transmission 10b is associated with a
transmission fluid cooler 36 of the vehicle 10. Ordinarily, this
transmission cooler 36 is built into a portion of the vehicle
coolant radiator and is an ATF-to-engine-coolant type.
Alternatively, the transmission cooler 36 may be configured as a
separate ATF-to-air heat exchanger, which is usually installed
behind the grill of the vehicle. In some cases, vehicles are
equipped with both types of ATF coolers. The cooler 36 is connected
in fluid flow to the transmission 10b by conduits 38 and 40, with
ATF flow directions in these conduits being indicated by the arrows
on FIG. 2. The conduits 38, 40, and cooler 36 cooperatively define
an external closed ATF circulation loop for the transmission 10b,
which external closed fluid circulation loop is indicated by
numeral 39 on FIG. 2.
Conduit 38 is shown in FIG. 2 with a portion of its length depicted
in dashed line. When the vehicle 10 is in normal operation, the
dashed line portion of conduit 38 is connected together, and fluid
flows from the transmission to the cooler 36 along this conduit.
However, during service of the transmission using machine 12, one
of the conduits 38 or 40 is interrupted as suggested in FIG. 2, and
the machine 12 is connected into the previously-closed ATF
circulation loop 39 for cooler 36. In FIG. 2, conduit 38 is the one
shown opened for connection of machine 12. However, either of the
conduits 38 or 40 may be so opened, dependent upon which one is
most easily accessible to the service technician on each particular
individual vehicle to be serviced. Either or both of the conduits
38 or 40 may be accessed for service of the transmission with
absolutely no difference in the effectiveness of the service
performed. In preparation
for and during the transmission service, the accessed one or both
of the conduits 38 or 40 is interrupted, and after the service is
complete the connection of the conduit is restored to its original
fluid flow continuity.
Machine 12 includes a fluid-flow rectifier assembly, indicated with
numeral 42. This rectifier assembly includes four nodes (or fluid
flow confluence and branching) respectively indicated with numerals
44, 46, 48, and 50; and also includes four check valves each
indicated with a respective numeral 52. The check valves 52 are
each disposed between a connected pair of the nodes 44-50, and are
oriented as shown in FIG. 2. As is seen in FIG. 2, hose 14 connects
to node 44, and the hose 16 connects to node 50. The check valves
52 are each oriented so that fluid can flow only to node 48 and
only away from node 46. Accordingly, no matter which way the hoses
14 and 16 are connected to the opened ends of the interrupted one
of conduits 38 or 40, ATF flow is always from one of nodes 44 or 50
to node 48, and from node 46 to the other one of nodes 44 and 50.
Node 48 is connected by a conduit 58 including a pressure gauge 54
and a flow meter 68 to the common port of a spring-loaded three-way
solenoid valve 56. The flow meter 68 has a visible pin-wheel or
turbine-type of indicator 68a, which is displayed on the front of
machine 12, as is seen in FIG. 1.
The solenoid valve 56 has a normally-open (N.O.) port from which a
conduit 58 connects to node 46. Accordingly, a closed loop fluid
flow connection is provided by machine 12, which when the machine
12 is connected as shown in FIG. 2, completes loop 39. This loop
within machine 12 is indicated on FIG. 2 with two loop arrows
referenced with numerals 39a and 39b. Loop 39a is a virtual loop
which actually is completed by fluid flow in loop 39b, as will be
described. During flush mode of operation as described above, the
machine 12 completes the circulation loop 39 by flow of ATF in the
internal loop indicated with numerals 39a and 39b of FIG. 2. During
this circulation of ATF in the machine 12, the service technician
can observe the available pressure provided by the internal pump of
the transmission 10b at gauge 54, seen on the front of machine 12
in FIG. 1.
Further considering the three-way solenoid valve 56, it is seen
that this solenoid valve includes a valve portion 56a and a
solenoid actuator portion 56b. The solenoid actuator portion 56b
includes an armature member 56c movably disposed within a solenoid
coil 60, and a spring 62 biasing the armature 56c toward a first
position. The armature member 58 interacts with the valve portion
56a so that when the armature 58 is in its first position the
common port is connected only to the N.O. port of the valve portion
56a. When the solenoid coil 60 is actuated electrically, armature
member 56c is moved to a second position (not shown) in which the
common port of the valve portion 56b is connected only to the N.C.
port of this valve portion. The N.C. port of solenoid valve 56
connects via a conduit 64 to one portion (a motor portion) of a
motor/pump unit 66. From this motor portion (indicated with numeral
66a), fluid flows via a hose 34 to the waste-fluid container
32.
The machine 12 is also provided with a float switch 70 at reservoir
28, which electrically allows connection of the common port of
solenoid valve 56 to the N.C. port only if a sufficient volume of
new ATF is in this reservoir, and which closes if the level of this
new ATF falls too low. Float switch 70 controls a relay 72 in
series circuit with all of the switch 30, solenoid coil 60, a motor
74, and the battery of the vehicle 10 via cable 18. When the
service technician closes switch 30, solenoid coil 60 and the motor
74 are both actuated if relay 72 allows (i.e., if the float switch
70 indicates a sufficient level of new ATF in the reservoir 28),
and the common port of solenoid valve 56 is switched from
communication with the N.O. port to communication to the N.C. port.
Thus, the internal closed ATF circulation loop of the machine 12
(recalling arrows 39a and 39b) is opened, and used ATF from the
transmission 10b flows to waste container 32.
Motor/Pump Unit
Considering now FIG. 3, it is seen that the motor/pump unit 66
includes a housing 76 defining an inlet port 76a and outlet port
76b from motor portion 66a. Similarly, the housing 76 defines an
inlet port 76c and outlet port 76d to and from a pump portion 66b.
The motor portion 66a and pump portion 66b are each defined by a
meshed pair of spur gears (respectively indicated with numerals 78,
80, 82, and 84. The housing 76 defines closely fitted chambers for
these meshed gears, which is conventional in the art of spur-gear
pumps and motors. However, in this case, the housing 76 also
journals a pair of connecting shafts, indicated with numerals 86
and 88. The shafts 88 and 86 drivingly connect the indicated spur
gears for rotation in unison, as is indicated by the arrows on FIG.
3. Thus, as used ATF flows through the motor portion 66a (from port
76a to port 76b) of motor/pump unit 66 the gears 78 and 80 are
forced to rotate as indicated, driving the gears 82 and 84 in
rotation via shafts 86 and 88. The motor/pump unit 66 is a
positive-displacement fluid motor/pump unit, with each side having
identically the same fluid displacement per rotation of the gears
78-84 (ignoring some slight and insignificant volume of fluid which
may leak from the motor portion to the pump portion of the
unit).
Further to the above, it is seen that according to the one
illustrated embodiment of the unit 66, the housing 76 carries a
pair of elongate plain journal bearings 90 (only a portion of each
being seen in FIG. 3 for clarity of illustration). These journal
bearings 90 are closely and precisely fitted to the shafts 86 and
88 so that these shafts (and the gears 78-84) are very free
running. Importantly, the close fitting of these journal bearings
and shafts is relied upon to effect a sufficient fluid seal between
the motor side and pump side of the motor/pump 66 so that only an
insignificantly small amount of ATF flows along the shafts 86, 88
without the use of a contact type of sealing element. Consequently,
no significant mixing of old ATF with new ATF takes place in the
motor/pump unit 66.
Those ordinarily skilled in the pertinent arts will recognize that
other sealing expedients are possible in motor/pump unit 66, and
which also provide for free running of the internal components of
this unit. For example, a labyrinth seal could be used along the
length of the shafts 86 and 88 to inhibit fluid flow between the
motor and pump portions of this unit, still without the use of a
contact sealing element. Alternatively, a low-friction type of
contact sealing element can be used on the shafts 86, 88. This may
take the form of, for example, a carbon ring face seal, or a
low-friction radial lip seal disposed between the housing 76 and
each of the shafts 86, 88. Because these sealing expedients are old
and well known in the pertinent arts, it is deemed that they need
not be illustrated in this application. In each case, the
motor/pump unit 66 can achieve motoring and pumping operation
utilizing only a relatively low fluid pressure provided by the
internal pump of transmission 10b. This makes transmission
servicing possible even with the engine 10a idling.
To recap the above, it is seen that in a fluid flush mode of
operation for the machine 10, the loop 39a/b is completed, and ATF
fluid from the transmission 10b flows through the machine 10 and
back to the transmission 10b. However, when the technician closes
switch 30, provided there is a sufficient quantity of new ATF in
the reservoir 28, the old ATF from the transmission 10b is directed
under the pressure of the internal pump of the transmission to
waste container 32. Simultaneously, it is desired that new ATF is
drawn from reservoir 28, flows from port 76c to port 76d of the
pump portion 66b of motor/pump unit 66, and is delivered to the
loop 39b via a check valve 90.
However, it has been discovered that some vehicles have automatic
transmissions of such low pressure or low flow rate that even
though the motor/pump unit 66 is extraordinarily free running, the
available pressure/flow from the internal pump of the transmission
is not sufficient. Accordingly, the present inventive apparatus 12
includes a electrically-driven assist pump 94 which is driven by
the drive shaft 74a of motor 74.
Importantly, the pump 94 and motor 74 impose a very low energy
demand on the electrical system of the vehicle 10 being serviced.
Also, the motor 74 and pump 94 together develop a small fluid
pressure, so small in fact that should the motor 74 and pump 94 be
running while a vehicle 10 under service is not running (i.e., so
that the internal transmission pump is not being driven by the
vehicle engine 10a) then the motor/pump 66 will not be driven by
the motor 74 and pump 94. Consequently, no withdrawal of old ATF
will occur under these conditions, and no new ATF will be put into
the transmission 10b. This is desirable, because the transmission
10b needs to be actively driven by the engine 10a during fluid
exchange to operate not only the internal pump of the transmission,
but also its control valves, torque converter, clutch actuators,
and other components.
However, in view of the above, it is seen that when the vehicle
engine 10a is running, and switch 30 is closed with a sufficient
quantity of ATF in reservoir 28, then and only then, the solenoid
valve 56 directs the used ATF from the loop 39a to waste container
32, and new AFT fluid from reservoir 28 is moved by pump 94 and the
pumping portion 66b of the motor/pump 66 to the transmission 10b.
This new ATF flows to the node 46, and then to the one of the hoses
14 and 16 which is connecting to the connection at the conduits 38
and 40 having the lower pressure. It will be understood in view of
the above, that fluid flow in the apparatus seen in FIG. 2 is being
impelled cooperatively by the internal pump of the transmission
10b, and by the pump 94 driven by motor 74. The motor/pump unit 66
acts to insure that the volume of old ATF substantially matches the
volume of new ATF provided to the transmission 10b.
Further, there is a progressive pressure drop along the length of
all flow paths, and the fluid flow at the connections to one of
conduits 38 and 40 will be differentiated from one another by this
fluid pressure differential. Accordingly, no matter which one of
the conduits 38 or 40 is interrupted for transmission service, and
no matter which way the hoses 14 and 16 are connected to the open
ends of the interrupted conduit 38 or 40, flow of used ATF will be
from one of these open ends of the interrupted conduit 38 or 40,
and flow of new ATF will be delivered by the machine 12 into the
other open end of the interrupted conduit. In other words, the
circulation loop 39 of the transmission is complete during flush
mode and appears to be complete during exchange mode also, but new
ATF is being supplied by the machine 12 in response to and in
matching volume to the pumping out of old ATF by the transmission
10b during exchange mode. During this fluid exchange mode of
operation, the technician can verify that fluid is flowing by
observing the indicator 68a of flow meter 68. Preferably, this flow
meter is a turbine type with a transparent wall through which the
technician can not only seen the spinning turbine, but can also
observe the color and turbidity of the ATF flowing from the
transmission to waste (i.e., this is visible on the front of
machine 12 as seen in FIG. 1). Thus, when the out-flowing ATF is
observed to change from the turbid burnt-umber of old fluid to the
clear bright red of new fluid, the technician knows that the
flushing and fluid exchanging operation is complete.
Assistance Pump 94 and Motor 74
Considering now FIGS. 4, 5, and 6, the details of a particularly
preferred pump 94 are presented. This pump 94 is in-unit with the
motor 74, although this need not be the case. In other words, other
types and styles of assist pumps may be employed without departure
from the spirit and scope of the present invention. For example, an
assist pump which is driven by a power source other than the
battery of a vehicle under service may be preferred in some
instances. An example of this type of assist pump is one that is
driven by an air motor receiving power from a source of shop air.
However, the present pump 94 is integral with its motor 74 and is
particularly preferred. Further, pump 94 is of a nutating, disk
design, which is also particularly preferred because of its
combination of low energy usage and low developed pressure
head.
Turning now to FIGS. 4-6 in combination with one another, it is
seen that the pump 94 includes a pump housing 96 having a cavity
96a therein which is circular in plan view (see FIG. 5). An inlet
98 leads to the cavity 96a, and an outlet 100 leads from this
cavity. The pump housing 96 includes housing sections 102 and 104
having confronting faces, with the confronting faces of the housing
section 102 having an annular groove 106, and the confronting face
of section 104 having an annular rib 108 received in this groove to
axially align the housing sections. An annular seal 110 is retained
cooperatively by the groove 106 and rib 108. Threaded fasteners
112a secure the housing sections removably together, while
fasteners 112b secure the pump 94 to the motor 74.
The cavity 96a is bounded by opposing wall sections 114a and 114b,
which are divergent conic sections. Within the divergent conic
sections, each wall section 114a and 114b, also includes a
respective part-spherical recess 116a and 116b. A stepped bore 118
opens on recess 116b, through which the shaft 74a of motor 74
extends into the cavity 96a. A seal member 120 is received in a
larger-diameter portion of the bore 118 and sealingly cooperates
with the shaft 74a to prevent fluid leakage from the cavity 96a
into the motor 74. The housing sections 102 and 104 each also have
a part-spherical peripheral wall section 122a and 122b, which
cooperatively define respective portions of openings 124a and 124b,
respectively leading to the inlet 98 and outlet 100.
A wobble plate member 126 is received in the cavity 96a for
nutating non-rotational movement. The wobble plate member will be
seen to effectively divide cavity 96a into an upper pumping chamber
96a' and a lower pumping chamber 96a". Further, the member 126
includes an interrupted circular plate portion 126a, which has an
interrupted part-spherical outer peripheral surface 126b, and a
part-spherical central hub portion 128. The plate portion 126
defines an interrupting slot 130 extending from the outer surface
126b (i.e., where the slot 130 interrupts this surface) radially
inwardly to a part-spherical joining surface 128a defined on the
hub 128 and spherically connecting the part-spherical surface
portions of hub 128 above and below the plate portion 126a.
The hub portion 128 defines a through cylindrical bore 132 into
which is received a nutation bushing 134. The nutation bushing 134
has a cylindrical outer surface 134a providing a bearing surface
rotationally cooperating with the inner surface of the member 126
at bore 132. Inwardly, the nutation bushing 134 defines a bore 134b
which is off-axis with respect to the surface 134a. That is, the
bore 134b is angulated relative to the surface 134a. The shaft 74a
of motor 74 is drivingly received into bore 134b. The motor shaft
74a extends generally perpendicularly to cavity 96. Consequently,
when the motor shaft 74a rotates, the member 126 can be driven in
nutation in cavity 96.
In order to prevent the member 126 from rotating with the shaft
74a, a separator member 136 is received pivotally at oppositely
extending trunnions 136' into aligned bores 138a and 138b
respectively defined in the housing sections 102 and 104. The
separator member 136 includes a wedge-shaped radially inwardly
extending plate part 136a, which terminates in a part-spherical
surface 136b confronting and sealingly cooperating with the plate
member 126 at surface 128a in slot 130. The separator member 136
also serves to separate or prevent fluid flow between the inlet
port 98 from outlet port 100 except by way of the pumping chambers
96a' and 96a".
An advantage of the nutating pump 94 is that it develops a
substantially constant flow volume. The pump 94 also has a low
power requirement from motor 74, so that this motor draws little
power from the vehicle battery via cable 18. Further, as was
explained above, the pump 94 develops little fluid pressure head.
An advantage of this low pressure head provided by the pump 94 in
the present instance is that the motor/pump unit 66 will not be
motored by fluid pressure delivered by the pump 94 alone. That is,
unless the vehicle 10 is operating (i.e., its motor 10a must be
running to drive the internal pump of transmission 10b) there will
be no fluid flow from the reservoir 28 into the transmission and no
used ATF will be discharged from the transmission.
However, and to repeat, when the service technician does activate
the machine 12 to exchange the old ATF from transmission 10b and to
replace
this old ATF with new ATF, in the event that the vehicle 10 is one
of those having low pressure or low flow from the internal
transmission pump, then the pump 94 will provide an adequate
assistance and the motor/pump unit 66 will be driven to exchange
the old ATF with new ATF on a matched volume basis. Further, in the
event the level of new ATF in reservoir 28 drops too low during the
service process, and even if the attendant is not present, the
float switch 70 will open electrically, and as a result the
spring-loaded solenoid will return valve 56a to the position
connecting the common port only to the N.O. port. This takes place
due to its own spring bias and the fact that the solenoid actuator
56b can be back-driven by this spring bias. Motor 74 is also shut
off, stopping operation of pump 94. Thus, in the event of cessation
of operation of the machine 12 (because of interruption of
electrical power, for example) or a shortage of fresh transmission
fluid, the loop 39 is restored, withdrawal of transmission fluid
stops, and the transmission 10b can not run out of fluid or be
damaged by dry running.
Such is also the case in the event that the engine 10a stops
running during a service procedure while the technician is not
present, for example, then some of the control valves and clutch
actuators, for example, would not be receiving new ATF and would
harbor old ATF if the exchange were continued by the machine 12.
However, the present machine 12 cannot continue such a fluid
exchange with the engine of the vehicle not running. In this way, a
proper and complete service of the transmission is assured, and
low-flow and low-pressure transmissions can be serviced with no
difference either in the service procedure or the time taken for
this procedure in the view of the service technician.
Those ordinarily skilled in the pertinent arts will understand that
when the process described above is complete, the technician
disconnects the machine 12 at the connections to one of the
conduits 38 or 40, restores the circulation loop 39, and sends the
old transmission fluid for disposal or to a recycling facility.
Hydraulic Rectifier 42
Turning now to FIGS. 7-10 in conjunction with one another, in FIGS.
7 and 8 is seen a particularly preferred embodiment of hydraulic
rectifier 42. This rectifier 42 includes a valve housing or body
140, which in this particular instance is a rectangular metallic
prismatic body. The body 140 is a single piece of metal, or is
unitary. This body defines four intersecting bores 142. These bores
all are stepped, blind, and each is substantially the same as the
others. In other words, each bore has only a single opening 144
outwardly on the body 140. At 144a each bore provides for
connection of a fluid conduit to the body 140 so that fluid is
communicated between the respective bore 142 and the conduit. In
the illustrated embodiment, the provision 144a is satisfied by an
outermost portion of each bore 142 defining a tapered pipe thread.
Thus, conduits (i.e., pipes) may be threadably and sealingly united
with the housing 140 at the bores 142. Alternative ways of
connecting fluid flow conduits to and from the rectifier 42 will
suggest themselves to those ordinarily skilled in the pertinent
arts.
In this preferred embodiment of the rectifier 42, the bores 142 are
arranged in mutually parallel pairs, with each pair being
perpendicular to the other pair. At a smaller diameter section 146
each bore communicates with one other of the four bores 142. As a
result, each bore 142 defines only a single opening 144 outwardly
on the housing 140, and extends from this opening to the
intersection with one other of the bores 142. However, internally
of the housing 140, all of the bores 142 are communicated with one
another to define a single flow path communicating all of the
openings 144 with one another.
Adjacent to the smaller diameter section 146 of each bore 142, a
respective larger diameter bore section 148 provides a step 150 on
the bore, with the step disposed away from the bore section 146.
Sealingly received in each respective bore 142 against the step 150
is a respective one of four unidirectional check valve assemblies
152. These check valve assemblies 152 are all substantially the
same, and will be described in greater detail below. However,
viewing FIG. 7, it is seen that the valves 152 are not installed
all the same way into their respective bores. In other words, for
the present it is sufficient to note that two valves 152 are
disposed with a head portion 154 of these valves disposed toward
the bore opening 144 having the single-headed arrow pointing
outwardly of this bore. Fluid may flow only out of this bore
opening. Two valves 152 are also installed with their head portions
154 disposed away from the bore opening 144 having the
single-headed arrow pointing into this bore opening. Fluid may flow
only into this bore opening. The result is that the other two bore
openings 144 (i.e., the ones seen in FIG. 7 with double-headed
arrows) allow fluid flow into or out of these openings.
Considering now FIGS. 9 and 10, it is seen that each valve assembly
152 includes a tubular body 156 having a cylindrical outer surface
156a for press fitting sealingly into the bore section 148 (i.e.,
into engagement with the step 150), and a stepped through bore
156b. The bore 156b defines a tapered seating surface 158 at one
end of the body 156, and an opposite shoulder 160. The conical head
portion 154 of a movable valve member 162 is sealingly engageable
with this tapered seating surface. The head portion 154 carries an
O-ring type of sealing member 164 disposed in a groove 166
circumscribing the head portion 154 and sealingly engaging the
seating surface 158 in a first (or closed) position for the valve
member 162, as is seen in FIG. 9. The valve member 162 includes a
stem portion 168 extending from the head portion 154 to a perforate
disk portion 170. The disk portion 170 defines several through
perforations 170a which allow fluid flow toward the head portion
154. Extending between the disk portion 170 and the shoulder 160 is
a coil compression spring 172. In view of the above (and as seen in
FIG. 9), it is seen that when fluid pressure is applied to head
portion 154 to urge this head portion toward the seating surface
158 (depicted in FIG. 9 by the arrow and character "P") the sealing
member 164 is tightly seated against the surface 158, and fluid
flow through the valve 152 is blocked.
On the other hand (as seen in FIG. 10), when fluid pressure is
applied to the head portion 154 to urge this head portion away from
the seating surface 158 (i.e., communicated to this side of the
head portion via the perforations 170a in the disk 170) then the
head portion 154 moves away from the seating surface 158,
compressing spring 172 slightly, and allowing fluid flow through
the bore 156b.
Alternative Torque-Motor Assistance
Finally, turning now to FIG. 11, another alternative embodiment of
the machine 12 is seen, which is the same in all respects with the
embodiment described above except as is set out below. Because of
this similarity, the features of FIG. 11 which are the same as or
which are analogous to those depicted and described above are
referenced on FIG. 11 using the same reference numeral used above,
and having a prime (i.e., ') added thereto. The embodiment of FIG.
11 does not include the motor 74 or pump 94 as described above.
Instead, assistance to low-flow and low-pressure automatic
transmissions in operating the fluid exchange function of the
machine 12 is provided by a torque motor 180 drivingly connected to
a modified motor pump unit 66'. The motor/pump unit 66' is like the
unit 66 described and depicted above, with the exception that it
provides for a torque transmitting connection 182 of the motor 180
to at least one of the shafts 86', 88'. In this way, the motor/pump
unit can be assisted to exchange fluid in low-flow and low-pressure
automatic transmissions. Thus, in this alternative embodiment,
assistance pump 94 and motor 74 as described above are not needed.
However, and consistently with the first embodiment described
above, the torque motor 180 and/or its coupling 182 to the
motor/pump unit 66' is selected such that it alone will not motor
the motor/pump unit 66'. In other words, the motor/pump unit 66' is
not operated as a pump in the absence of fluid flow provided by the
internal pump of an automatic transmission connected with a running
engine. Restated, the cooperative effect of fluid pressure provided
by the operating internal pump of an automatic transmission and of
motor/pump unit 66' assisted by motor 180 are required in order to
effect exchange of fluid in an automatic transmission using the
embodiment seen in FIG. 11.
While the present invention has been depicted, described, and is
defined by reference to a single particularly preferred embodiment
of the invention, such reference does not imply a limitation on the
invention, and no such limitation is to be inferred. The invention
is capable of considerable modification, alteration, and
equivalents in form and function, as will occur to those ordinarily
skilled in the pertinent arts. Thus, the depicted and described
preferred embodiment of the invention is exemplary only, and is not
exhaustive of the scope of the invention. Consequently, the
invention is intended to be limited only by the spirit and scope of
the appended claims, giving full cognizance to equivalents in all
respects.
* * * * *